Test settings persistence ownership, ordering and failure isolation

tools/chatgui-android/router-tests/src/test/kotlin/com/utun/chat/data/SettingsOperationsTest.kt

@@ -0,0 +1,40 @@
+package com.utun.chat.data
+
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.*
+import org.junit.Test
+
+class SettingsOperationsTest {
+    @Test fun acceptedSaveSurvivesUiCancellationAndRestartWaitsForItsCommit() = runTest {
+        val owner = SettingsOperations(this) { _, _ -> }
+        val committed = CompletableDeferred<Unit>(); val order = mutableListOf<String>()
+        val save = owner.submit("name") { committed.await(); order.add("commit") }
+        val second = owner.submit("runtime") { order.add("apply") }
+        val ui = launch { save.await() }; ui.cancel()
+        val restart = async { owner.awaitIdle(); order.add("restart") }
+        assertTrue(order.isEmpty()); assertFalse(save.isCancelled)
+        committed.complete(Unit); save.await(); second.await(); restart.await()
+        assertEquals(listOf("commit", "apply", "restart"), order)
+    }
+    @Test fun failedPersistenceCannotRunTheFollowingRuntimeUpdateOrKillTheQueue() = runTest {
+        val logs = mutableListOf<String>(); val owner = SettingsOperations(this) { _, message -> logs.add(message) }
+        var runtime = false
+        val failed = owner.submit("volume") { throw java.io.IOException("disk rejected"); @Suppress("UNREACHABLE_CODE") runtime = true }
+        assertTrue(runCatching { failed.await() }.exceptionOrNull() is java.io.IOException)
+        assertFalse(runtime); assertTrue(owner.failed.value); assertTrue(logs.any { "disk rejected" in it })
+        owner.submit("retry") { runtime = true }.await()
+        assertTrue(runtime); owner.dismissFailure(); assertFalse(owner.failed.value)
+    }
+    @Test fun cancelledBarrierWaiterCannotCancelAnAcceptedChange() = runTest {
+        val owner = SettingsOperations(this) { _, _ -> }
+        val gate = CompletableDeferred<Unit>(); var saved = false
+        val change = owner.submit("stereo") { gate.await(); saved = true }
+        val waiter = launch { owner.awaitIdle() }; waiter.cancel()
+        gate.complete(Unit); change.await(); assertTrue(saved); assertFalse(change.isCancelled)
+    }
+}